The application of pulsed ultrasonic devices for B-mode, Doppler imaging and determination of the velocity changes across arterial stenoses is under study. The carotid artery bifurcation is a common site for atherosclerosis to develop which can lead to transient ischemic attacks and stroke. The ultrasonic devices being tested provide information relative to the geometric change produced by the plaque, the presence of calcification in the wall or the lesion, and the changes in flow that occur across the lesion itself. Those patients who undergo arteriography are having the x-rays read by radiologists unaware of the test results. The arteries are classified as normal, less than 10% stenosis, 10-49%, 50-99% diameter reduction and total occlusion. The ultrasonic studies are classified according to both changes in local geometry and flow disturbances. The data will be analyzed in terms of the sensitivity and specificity of the testing procedures. The goal is to not only identify the presence of disease in the carotid artery, but develop some quantitative indices which may be useful in determining both the degree of arterial narrowing and its effect on the flow pattern that results.